Manufactured floor coverings are in widespread use in both residential and commercial settings. These floor coverings vary widely, both in the type of material of which the coverings are constructed, and in the manner in which the floor coverings are installed. The exposed surface of many of these floor coverings is constructed either of carpeting or a smooth durable material. Carpeting surfaces can be woven, tufted, fusion bonded or otherwise constructed. Smooth and durable surfacing materials can be derived from virtually innumerable organic, inorganic, man-made, and natural compositions.
Many floor coverings are constructed of one or more layers. These layers often are derived from differing materials, and serve different functional purposes. Most layered floor coverings can be characterized as having two principal layers, a backing layer and a face layer. In turn, the backing and face layers can be comprised of one or more sublayers. As used here, the term "backing" or "backing layer" refers to the layer (including sublayers) of the floor covering that is secured directly to or lies directly against the floor. The term "face layer" refers to the layer (including sublayers) that is positioned on top of the backing, and provides the visible surface of the floor covering after it has been installed.
Floor coverings are often manufactured and packaged in rolls at the factory. To install the floor covering one simply rolls out the floor covering at the installation site, cuts it to size, and, if desired, secures the covering to the floor. Other floor coverings are manufactured as tiles and installed on or secured to a floor as such. Both tile and roll-goods floor coverings can be constructed entirely at the factory with all the layers of the floor covering secured together at the factory. Other floor coverings require that the backing layer first be applied on-site, and that a face layer be applied subsequently to the backing layer.
Chemical adhesives are often used to secure together backing and face layers. Chemical adhesives generally perform well in floor coverings, and provide a durable and intimate bond between floor covering layers. Chemical adhesion is, however, an impediment to separating the face layer from the backing, which often must be done before applying a new face layer to an existing backing, or recycling the layers of the floor covering. Many chemical adhesives provide too much adhesion between the two layers, and prevent later separation at the interface of the layers. Attempts to separate floor coverings into different layers often destroy one of the layers. If the layers are successfully separated, they are most often not separated cleanly.
The prior art discloses several ways to construct layered floor coverings that can be separated into layers after use. Parking, U.S. Pat. No. 4,769,895, discloses interlocking dust control mats. The mats have cleats on the bottom that mate with cleats molded to the top of an interconnecting strip that is laid on the floor. Layman et al., U.S. Pat. No. 4,489,115, discloses two adjacent pieces of artificial turf that are bound together at their edges by a mated surface interlocking fastener such as Velcro.TM. or 3M Scotchmate.TM. located on both the bottom of one edge and the top of the other edge Another means to releasably secure two layers together is disclosed in Goodwin et al., U.S. Pat. No. 4,824,498 and Raws, U.S. Pat. No. 5,116,439. Goodwin and Raws each disclose an additional layer that is incorporated into the floor covering between the face layer and backing layer. The additional layer splits when the face layer and backing layer are pulled apart with part of the additional layer adhering to the top layer, and the other part adhering to the bottom layer.